CONCURRENT USE OF TETRACYCLINES WITH ORAL CONTRACEPTIVES MAY RENDER ORAL CONTRACEPTIVES LESS EFFECTIVE. ANTACIDS CONTAINING ALUMINUM, CALCIUM , OR MAGNESIUM, FOODS AND SOME DAIRY PRODUCTS, BISMUTH, IRON,ZINC IMPAIR ABSORPTION. NEPHROTOXIC EFFECTS ARE POTENTIATED BY DIURETICS, METHOXYFLURANE AND OTHER NEPHROTOXIC DRUGS. WITH RETINOIDS INCIDENCE OF BENIGN INTRACRANIAL HYPERTENSION IS INCREASED. CONCENTRATION OF LITHIUM, DIGOXIN, THEOPHYLLIN, ORAL ANTICOAGULANTS IS INCREASED. DECREASED EFFICACY OF ORAL CONTRACEPTIVES. ANTAGONISE PENICILLINS. ANTACIDS CONTAINING ALUMINUM, CALCIUM, OR MAGNESIUM IMPAIR ABSORPTION AND SHOULD NOT BE GIVEN TO PATIENTS TAKING ORAL TETRACYCLINE. FOODS AND SOME DAIRY PRODUCTS ALSO INTERFERE WITH ABSORPTION. ORAL FORMS OF
TETRACYCLINE SHOULD BE GIVEN 1 HOUR BEFORE OR 2 HOURS AFTER MEALS. SUCRALFATE & CIMETIDINE HAS NO EFFECT ON ABSORPTION.